Refrigerant metering system and method

Abstract

A refrigerant metering system/method incorporating a manual expansion valve (MEV), condenser isolation valve (CIV), flow isolation valve (FIV), and evaporator isolation valve (EIV) is disclosed. The MEV is configured to replace a conventional automated expansion valve (AEV) that controls a refrigerant flow valve (RFV) that is positioned in a heating, ventilation, and air conditioning (HVAC) system between a refrigerant condenser coil (RCC) and a refrigerant evaporator coil (REC) and permits manual metering of refrigerant by the RFV from the RCC to the REC and also allows complete shutoff of refrigerant flow by the RFV from the RCC to the REC. The MEV allows rapid HVAC repair and restoration of service where a replacement AEV is not readily available. The CIV/FIV/EIV are positioned in the refrigerant flow lines to permit the AEV and/or REC to be isolated from HVAC refrigerant flow for repairs to the AEV and/or REC.

What is claimed is: 
     
       1. A refrigerant metering maintenance method comprising:
 (1) Deactivating refrigerant flow in an HVAC system ( 2801 ); 
 (2) Installing a condenser isolation valve (CIV) between a refrigerant condenser coil (RCC) refrigerant outlet port and a refrigerant flow valve (RFV) input port on said HVAC system ( 2802 ); 
 (3) Installing a flow isolation valve (FIV) between a refrigerant outlet port of said RFV and a refrigerant evaporator coil (REC) input port in said HVAC system ( 2803 ); 
 (4) Installing an evaporator isolation valve (EIV) between a refrigerant outlet port of said REC and a refrigerant compressor (RFC) in said HVAC system ( 2804 ); 
 (5) Evacuating refrigerant from said REC using Schrader ports present on said CIV and/or said FIV and/or said EIV ( 2805 ); 
 (6) Opening said CIV on said RCC to connect said RCC to said RFV ( 2806 ); 
 (7) Opening said FIV on said RFV to connect said RFV to said REC ( 2807 ); 
 (8) Opening said EIV on said REC to connect said REC to said RFC ( 2808 ); 
 (9) Recharging said REC with refrigerant using said Schrader ports on said CIV and/or said FIV and/or said EIV ( 2809 ); 
 (10) Activating refrigerant flow in said HVAC system ( 2810 ); and 
 (11) Terminating said refrigerant metering maintenance method ( 2811 ); 
 wherein: 
 said RFV is controlled by a manual expansion valve (MEV); 
 said MEV is configured to mechanically couple to said refrigerant flow valve (RFV); 
 said MEV manually controls mechanical operation of said RFV; 
 said MEV comprises:
 (1) manual retention cap (MRC); 
 (2) manual control rod (MCR); and 
 (3) manual locking fastener (MLF); 
 
 said MEV mechanical coupling is configured to allow attachment of said MEV to said RFV in an existing heating, ventilation, and air conditioning (HVAC) system; 
 said MEV mechanical coupling is configured to be removable and allow said MEV to temporarily replace an automated expansion valve (AEV) that has been removed from said RFV in said HVAC system; 
 said RFV comprises a valve input port (VIP) and valve output port (VOP) coupled together by a valve transfer port (VTP); 
 said VIP, said VOP, and said VTP are mechanically coupled in a unitary valve containment structure (VCS); 
 said RFV comprises a valve metering piston (VMP) that is positioned within said VTP and meters refrigerant flow between said VIP and said VOP; 
 said VMP comprises a valve control rod (VCR) that is positioned within a control rod port (CRP) within said VCS; 
 said RFV comprises a threaded valve control port (VCP) having male threads; 
 said CRP is contained within the perimeter of said VCP; 
 said RFV comprises a valve spring control (VSC) acting against said VMP to resist movement of said VMP; 
 said VSC action against said VMP acts to push said VMP against said VCR and allow flow from said VIP to said VOP through said VTP; 
 said MRC comprises an control interior cavity (CIT) having female threads that conform to male threads of said VCP; 
 said MRC comprises a threaded control port (TCP) along a longitudinal axis of said CIT; 
 said MCR comprises a cylindrical control rod (CCR), a threaded adjustment shaft (TAS), and an adjustment control head (ACH); 
 said CCR comprises a cylinder having a control rod diameter (CRD) conforming to said CRP; 
 said CCR, said TAS, and said ACH are mechanically connected in a linear combination along a common longitudinal radial axis (LRA); 
 said MLF comprises a female fastening member (FFM) having a central threaded interior (CTI); 
 said TAS comprises threads that conform to said CTI; 
 said MCR is configured to allow adjustment of said VMP through pressure applied to said VCR by said CCR to overcome pressure applied to said VMP by said VSC; and 
 said adjustment of said VMP is configured to permit refrigerant flow from said VIP to said VOP to be adjusted from unmetered refrigerant flow through said RFV to zero refrigerant flow through said RFV. 
 
     
     
       2. The refrigerant metering method of  claim 1  wherein said RFV comprises connection fittings selected from a group consisting of: soldered; brazed; flared; compression; and national pipe thread (NPT).